Various tools are used in hydrocarbon exploration and production to measure properties of geologic formations during or shortly after the excavation of a borehole. The properties are measured by formation evaluation (FE) tools and other suitable devices, which are typically integrated into a bottomhole assembly. Sensors are used in the FE tools to monitor various downhole conditions and formation characteristics.
Environments in which FE tools, drilling equipment and other drillstring components operate are very severe, and include conditions such as high downhole temperatures (e.g., in excess of 200° C.) and high impact vibration events. Furthermore, rig operators are currently using the tools to perform mission profiles that have previously been impossible, thereby increasing the stress on the tools. Simultaneously, customers are demanding high reliability to help them prevent costly downhole failures.
To date, periodic maintenance has been the most widely spread method by which tool reliability is maintained. As time progresses, there has been a shift toward condition based maintenance, which, as of today, uses design guidelines and rough thresholds for nominal operation to assess individual tool health. Present techniques, however, are inferior in that a large amount of telemetry data collected during operation that has yet to be effectively harnessed.